The general objective of this study is to add to the available measures for assessing sleep quality in preschool and early school-age children. Sleep is the most notable behavior during childhood, and poor sleep is related to children's psychosocial functioning and socially significant health problems, such as diabetes, asthma, and hypertension. Many questions concerning the significance of normal and abnormal sleep remain unanswered. Measures for collecting data with large samples are limited. Multiple methodologies are needed to address a broad range of sleep-related questions in a variety of fields. This project will assess the construct validity of a new research measure of sleep quality, the Children's Sleep-Wake Scale (CSWS), by demonstrating that (a) scores on the CSWS correlate adequately with other subjective and objective measures of sleep (actigraphy and sleep diaries), and (b) subscale scores on the CSWS will differ as a function of children's standing on variables known to be related to sleep. Data will be collected on a total of 120 children between the ages of 2 and 8 years. This sample will be comprised of four groups of children: (1) exceptionally good sleepers, (2) children with nocturnal asthma, (3) children with noncompliant behavior, and (4) children from the general population. Caretakers will be administered the CSWS. Then, sleep-wake diary and actigraphic data will be collected for 7 days. At the end of this period, the caretakers will again complete the CSWS.